1. Field of the Invention
The present invention relates to an ice making machine in which ice making water is gradually frozen in a static or flowing condition on the surface of an ice making plate to be formed into ice.
2. Discussion of the Prior Art
Disclosed in Japanese Utility Model Publication No. 1-31899 is an ice making machine of the type which includes an inclined ice making plate with freezing means arranged to be supplied with ice making water from its upper portion for gradually forming the water into ice during flowing down thereon. There has been provided an ice making machine of the type which includes a plurality of ice making cells arranged to be supplied with ice making water ejected therein from their bottoms for forming the water into ice. There has been also provided an ice making machine of the type which includes an upright ice making plate arranged to be supplied with ice making water from its upper portion for forming the water into ice. In use of these ice making machines, it has been attempted to rise the cooling temperature of the ice making plate or change the material of the ice making plate to a material of low heat transfer coefficient so that crystal growth of the ice is delayed to produce hard clear ice of high transparence in a single crystal.
In such an attempt as described above, the ice making plate has been made of a metallic material such as copper, stainless steel, aluminum or the like to delay crystal growth of the ice. However, it was unable to efficiently produce the ice in the form of a large single crystal. The produced ice was in the form of fine multi-crystal particles which cause irregular groove-like stripes in the surface of the ice when molten at their crystal grain boundaries. Thus, the transparence of the ice is lost, and the ice becomes fine fragile crystals.